elevationplane.java

world wind java sdk 源码

package gov.nasa.worldwind.render;

import gov.nasa.worldwind.geom.LatLon;
import gov.nasa.worldwind.render.airspaces.Polygon;
import gov.nasa.worldwind.util.*;

import javax.media.opengl.GL;
import java.util.*;

/**
 * Renders a textured plane at a given elevation.
 *
 * @author Patrick Murris
 * @version $Id: ElevationPlane.java 10816 2009-05-04 02:54:51Z patrickmurris $
 */
public class ElevationPlane extends Polygon
{
    private Object imageSource;
    protected WWTexture texture;
    private double imageSize = 500; // meter

    protected OGLStackHandler osh = new OGLStackHandler();

    public ElevationPlane()
    {
        this.getRenderer().setEnableLighting(false);
    }

    /**
     * Get the source for the fill pattern image. Can be a file path to a local image or
     * a {@link java.awt.image.BufferedImage} reference.
     *
     * @return the source for the fill pattern image - can be null.
     */
    public Object getImageSource()
    {
        return this.imageSource;
    }

    /**
     * Set the source for the fill pattern image. Can be a file path to a local image or
     * a {@link java.awt.image.BufferedImage} reference.
     *
     * @param imageSource the source for the fill pattern image - can be null.
     */
    public void setImageSource(Object imageSource)
    {
        this.imageSource = imageSource;
        this.texture = null;
    }

    /**
     * Get the real world image size in meter. The image source is repeated so that one tile covers this distance.
     *
     * @return the real world image size in meter.
     */
    public double getImageSize()
    {
        return this.imageSize;
    }

    /**
     * Set the real world image size in meter. The image source will be repeated so that one tile will
     * covers this distance.
     *
     * @param sizeInMeter the real world image size in meter.
     */
    public void setImageSize(double sizeInMeter)
    {
        this.imageSize = sizeInMeter;
    }

    // Airspace Polygon overload
    protected void doRenderGeometry(DrawContext dc, String drawStyle, List<LatLon> locations, List<Boolean> edgeFlags)
    {
        this.beginRendering(dc);
        try
        {
            // Setup texture coordinates generation
            this.setupTextureState(dc);

            // Draw
            super.doRenderGeometry(dc, drawStyle, locations, edgeFlags);
        }
        finally
        {
            this.endRendering(dc);
        }
    }

    protected void beginRendering(DrawContext dc)
    {
        // TODO: review attributes
        GL gl = dc.getGL();
        osh.pushAttrib(gl, GL.GL_COLOR_BUFFER_BIT // for alpha func
            | GL.GL_ENABLE_BIT
            | GL.GL_CURRENT_BIT
            | GL.GL_DEPTH_BUFFER_BIT // for depth func
            | GL.GL_TEXTURE_BIT // for texture env
            | GL.GL_TRANSFORM_BIT);
        osh.pushTextureIdentity(gl);
    }

    protected void endRendering(DrawContext dc)
    {
        osh.pop(dc.getGL());
    }
    
    protected void setupTextureState(DrawContext dc)
    {
        WWTexture texture = getTexture();
        if (texture == null)
            return;

        if (!texture.bind(dc))
            return;

        GL gl = dc.getGL();
        // Texture coordinates generation
        double[] sPlane = {1, 0, 0, 0}; // TODO: define planes relative to shape center?
        double[] tPlane = {0, 1, 0, 0};
        gl.glTexGeni(GL.GL_S, GL.GL_TEXTURE_GEN_MODE, GL.GL_OBJECT_LINEAR);
        gl.glTexGeni(GL.GL_T, GL.GL_TEXTURE_GEN_MODE, GL.GL_OBJECT_LINEAR);
        gl.glTexGendv(GL.GL_S, GL.GL_OBJECT_PLANE, sPlane, 0);
        gl.glTexGendv(GL.GL_T, GL.GL_OBJECT_PLANE, tPlane, 0);
        gl.glEnable(GL.GL_TEXTURE_GEN_S);
        gl.glEnable(GL.GL_TEXTURE_GEN_T);
        // Pattern scaling
        gl.glMatrixMode(GL.GL_TEXTURE_MATRIX);
        gl.glScaled(1 / this.imageSize, 1 / this.imageSize, 1f);
        // Texture setup
        gl.glEnable(GL.GL_BLEND);
        gl.glBlendFunc(GL.GL_ONE, GL.GL_ONE_MINUS_SRC_ALPHA);
        gl.glEnable(GL.GL_TEXTURE_2D);
        gl.glTexEnvf(GL.GL_TEXTURE_ENV, GL.GL_TEXTURE_ENV_MODE, GL.GL_MODULATE);
        gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_S, GL.GL_REPEAT);
        gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_T, GL.GL_REPEAT);
    }

    protected WWTexture getTexture()
    {
        if (this.texture == null && this.imageSource != null)
            this.texture = new BasicWWTexture(this.imageSource);

        return this.texture;
    }


}